We have a lot to unpack with this historic and crippling ice storm that most heavily impacted NE Ulster County. Some of the graphics may seem busy, as there is much to convey. Best bet is to take some time to orient yourself with the map, take it all in and allow it to digest. Then come back to this next part where we will break down the individual aspects of the map, you can continually refer back to it as we progress, sound like a plan?
Ok.. Let’s nerd out..
Understanding the Map:
- There are two distinct areas of colors on the map, the smooth hatched areas on the map of Red’s, Orange’s and Green’s are an overlay of the Central Hudson Outages that were stitched together into a single image, they represent large areas of outages while the smaller dots are more isolated outages (This pieced together outage map was created by follower Jonathan Rhea). The other Blue, Green,Yellow,Orange and Red areas are a topographic relief map showing the topography of the Catskills with Blue and Green showing Valley’s and lower elevations while Orange and Red represent the higher terrain. We have added a red line showing appox where the 1000′ elevation contour begin’s and is marked by arrows with (1000ft).
- There Is a Solid Black Line the works its way throughout the map, this represents the boundaries of Central Hudson’s service area.
- The Blue Hatched Line that runs SW to NE across the top of the map is the appox location of the stalled cold front early Thursday AM.
- Three Light Blue Fuzzy Arrow’s represent NE winds.
- Three Thin, Dark Blue Arrow’s represent cold air draining down the valley floor.
- The Big Red L is representing the multiple waves of low pressure that traveled West to East along the Cold Front.
- Around The Map you’ll find the words Sleet,Rain,Freezing Rain– this represents the primary precipitation type during the storm in those locations, for reference.
- Two Stars, connected by a line these are marking two specific locations- Claryville and High Falls with the elevations of each town noted and the distance (As the Crow Flies) between them.
I know, it’s a lot to take in but there isn’t many ways to simplify the complexity of microclimates, power outages and topography!
Lets paint the picture of the set up leading into the storm on Thursday, model data had been consistently showing a moderate to severe icing event leading up to the storm, but the location of the heaviest icing, the amount of accretion and duration was not so consistent. Model’s continued to shift the area of impact wildly with the epicenter shifting from the lower Hudson Valley to Northern Hudson Valley and areas in-between.
Why?
The models were struggling with the speed and location of the cold front, and this was a very critical part of the forecast. Just to the North of the cold front was a thicker layer of cold air which supported Sleet, and even further north from there was the thickest layer of cold air which support 12-18″ of snow across the Southern Adirondacks. Just how quickly the front moved south would determine how long any one area stayed under the influence of these different precipitation types and how much would fall. The models leaned toward a slow moving front that would cause most areas to cool enough for rain to change to a brief period of freezing rain and then change to sleet and end as snow. This would lead to light icing, 1-2″ or sleet and a final coating of snow.
Despite the conflicting data, we began to raise the alarm on freezing rain and the chance that colder air would funnel down the Hudson River Valley and lead to a longer period of freezing rain, we even highlighted Ulster County as changing to Freezing Rain as soon as 11pm with up to .35″ of freezing rain. Modeling showed the possibility of freezing rain accretion exceeding .75″ across parts of the region, again not very consistent on where, in addition it is important to note that forecast modeling does a very poor job in forecasting ice accretion and is typically overdone 9 out of 10 times, the correct forecasting method is to greatly reduce the amount shown on modeling.
Now let’s talk about what happened to make this a “Perfect Storm” for Ulster County.
The aforementioned cold front did not progress as modeled it in fact it nearly stalled to our north, the location of the nearly stalled front is noted on the map. The cold air north of this frontal boundary was thick enough to support sleet, one only needs to travel along the thruway to see the sharp line between heavy icing and tree damage and nothing north of Saugerties. To put a visual on what we mean by “thickness” of the cold here is a diagram to show a cross section of the atmosphere and how the thickness of the 32 degree or less air impacts the type of precipitation that falls.
Remember cold air is dense and heavy, it will follow the lowest and least resistant path, open your top freezer door and cold air sinks to your feet, warm air is heavier and lighter and rides over colder air. On this diagram the cold front was located on the line between sleet and freezing rain, areas around Albany received up to 4″ of pure sleet and the Adirondacks up to 16″ of snow, while mostly rain fell across NYC. So imagine this image laid three dimensionally over the region with NYC to the south in the rain, Adirondacks to the North and our region right in the middle, as the cold front continued south the colder air behind it became thicker and changed the precipitation types alone the way. This is why sleet and freezing rain did eventually fall and caused icing across parts of southern Dutchess and Ulster and Orange later in the day on Thursday. Hope this helps give a good idea of the atmosphere over our heads and across the region for this event.
To understand what caused Ulster County to be the epicenter of this event we would have to go back millions of years to when glaciers miles thick progressed south through the Hudson Valley and while doing so they rounded off the tops of our Catskills and carved out the river valley and depostiing the till into what is now known as Long Island. When these glaciers melted they left behind massive inland lakes, one of which eventually burst and washed out and further scoured the river valley, water once filled the valley and the eastern escarpment of the Catskills Mountain were is shoreline. One can see and appreciate this from Overlook Mountain looking down into the Valley or looking west from the Rhinecliff Bridge. To bring the glacial period full circle to an ice storm last week, I will need your imaginations.
Let’s imagine the cold front as noted on the map is the dam of the glacial lake holding back in this case cold air. Now the cold air is also dammed up along the Northern Catskills, cause like water the cold air is heavy and dense and is only located in the bottom 1000′ of the atmosphere, therefore in cannot penetrate the higher topography of the Catskills . Now look back to the map… go ahead.. i’ll wait…. see that 1000′ line that cuts though Saugerties and meanders NNW that the sharp rising topography of the Catskill Escarpment and in this case its now the shoreline of a flood of cold air. Cold air behind the front, taking the path of least resistance was able to spring a leak in our dam of cold air, the cold air was able to bleed down the valley floor and into Northern Ulster and Dutchess County as noted by are three solid blue arrows, almost like a topographic drain plug had been pulled. The partially frozen river, frozen over Ashokan Reservoir aided in the sustaining of the cold air.
As this cold air drained south there was also a notable NE wind element at the lower levels, this aided in advecting that bleeding cold air into NE Ulster County, from there the lowlands and topography of Ulster allowed the cold air to flood west until it was once again blocked by the topography of the Eastern Catskills. One can even see on the map where colder air led to more outages on the western side of the Shawangunk Mountains vs the SE side as cold air was stacked, funneled and flooded into the local typography. Using the Central Hudson Outage concentrations as the indicator of the level of icing is a great gauge of where cold air was allowed to maximize icing, the outage map was manipulated in no way, it instead aligns perfectly with the topography.
Remember this was a longer duration event because it was multiple waves of low pressure traveling along this boundary, each one brought a new wave of precipitation while also enhancing the warmer air aloft due to the counter clockwise rotation around the low pressure, the resulted in a “warm nose” of air in the upper atmosphere which was being consistently wedged beneath by colder air at the surface.
This brings us to our two starred locations on the map ( This data from the NY Mesonet Network) –
Look at the incredible effect and efficiency the land was able to have on allowing the cold air to drain south and under cut the warmer air aloft. Despite Claryville being nearly 1300′ higher in elevation, High Falls dropped below freezing a full 12 hours earlier, with Claryville only dropping below 32 degrees when the front itself finally slugged its way south through the region. This would lead to Ulster County receiving freezing rain for 12-14 hours longer than any other location in the region. So why was NE Ulster harder hit? Because NE Ulster was closest to the source of the cold air, as the cold air drained south is moderated as it drained further and further from its source while battling the warmer air in place before its arrival. A drive though this region post storm showed isolated pockets of heavier accretion, in almost all of these situations there were notable low spots in elevation where colder air was able to settle or areas where local topography slowed the progression of the cold air allowing it to pile up. Icing did eventually occur in other locations and even some higher elevations, but this was due to the arrival of the cold front as it progressed south and wedged the colder air into other parts of the region.
Just how bad was the icing in parts of Ulster County, here is a photo from Josh Vogt from Hurley NY showing ice accretion on a single blade of grass..
This is very efficient accretion aided by light winds, light precipitation rates and temps that cooled into the mid 20’s, these factors combined led to maximum icing efficiency and led to amounts of .25-.80 of ice, Here is an example of how that falls on the scale of icing impacts. This led to largest amassing of utility workers in Central Hudson history, 2000+ down lines, hundreds of closed roads and massive tree damage across the region. Outages began as early as 4AM on Thursday and some persist as of this posting at 9pm on Tuesday!
This was Historic,Crippling and Catastrophic icing event, Ulster Counties impacts were not worsened by tree trimming, as Central Hudson trims trees on a cyclical basis in all of its coverage areas. This was in fact a perfect storm of meteorological and topographical influences, the led to a very targeted impact zone by forces that have been set in motion for millions of years. The same peaks and valleys that led to the creation of the HVW zone map, the same reasons our region is so unique and diverse in its weather and the very same reasons that led a child to become obsessed with the weather and create this page, while simotainously inflicted another child with the same obsession and causing him to eventually become part of HVW as well.
We at HVW would like to take a moment to thank all of the brave Utility Workers, Local FD’s,Local PD’s,OEM’s, Road Maintenance Crews, Out of State Mutual Aid, Local Leadership and every brave soul who ventured out to assist and help during the storm. We try our best to keep everyone ahead of and prepared for all of natures surprises, but all of you are there when the inevitable emergencies and destruction occurs. In addition our thoughts are with everyone who sustained damage from this storm, we can only hope your recovery is swift.
THANK YOU!! and Remember to Keep Calm and Weather On!
